Model Construction of String-shaped Flexible Object and Accuracy Evaluation of Constructed Model Using Robot Arm

Abstract

Recently, many researchers have investigated robot automation for rigid objects. However, typical flexible objects, including string-like objects such as cables and tubes, are widely used as industrial media for signal transmission and fluid transport. In addition, wires and ropes are used for operations such as fixing and packaging. When the target object is a rigid body, only its position and orientation change in response to manipulation. However, with flexible objects, the shape itself is deformed by manipulation, which poses a problem in modeling methods. Therefore, in this study, a multi-link model based on rigid body dynamics is employed to represent dynamic shape change as an object. The object is divided into an arbitrary number of parts and approximated as a set of rigid body elements. Each element is connected by springs and dampers acting in axial and rotational directions to represent physical properties. For modeling and simulation, the numerical analysis software MATLAB is used. The accuracy of the model is evaluated by comparing the model with objects manipulated on the surface by the robot arm. Furthermore, contact with a cylindrical obstacle is modeled, an experiment is conducted to bring the object into contact with the obstacle, its movement is simulated, and the reproduction accuracy is evaluated by comparing the experimental and simulated values.